Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

IGCSE Biology > Topic 5 > Flashcards

Topic 5 Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What is asexual reproduction?

A

A process resulting in the production of genetically identical offspring from one parent.
- No fusion of gametes: no mixing of genetic information
- Produces clones
- No genetic variation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What examples of organisms asexually reproduce?

A

Bacteria, fungi, small plants, animals, potatoes, bulbs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are 2 advantages of asexual reproduction?

A
  1. Faster
  2. Less energy required
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the disadvantage of asexual reproduction?

A

Offspring are all genetically identical - doesn’t produce genetic variation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is mitosis?

A

Nucleas division giving rise to genetically identical cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is sexual reproduction?

A

A process involving the fusion of the nuclei of two

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does asexual reproduction occur?

A

Mitosis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is mitosis?

A

Nuclear division giving rise to genetically identical cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What happens during the process of mitosis?

A

During mitosis the DNA/chromosome replicates, then the cell divides. Half of the chromosomes will move into each divided cell, creating the two daughter cells with the same number of chromosomes as the parent cell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is sexual reproduction?

A

The process involving the fusion of the nuclei of two gametes to form a zygote and the production of offspring that are genetically different from each other.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is fertilisation?

A

The fusion of the nuclei of gametes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the features of the nuclei of gametes and nucleus of zygote?

A

Gamete = haploid
Zygote = diploid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is meiosis used for and what does it produce?

A

Used for making gametes. Produces 4 haploid daughter cells with half the chromosome number of a regular body cell (diploid).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why is meiosis important for reproducing?

A

So the offspring will have a diploid number of chromosomes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Advantage of genetic variation in the wild:

A

Genetic variation means that organisms can better survive changes in the environment. Some individuals may die, but as the population is genetically diverse, some will have traits to survive.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Advantage of genetic variation in crops:

A

Having crop plants that are genetically different to one another is important for ensuring the crop can survive environmental change.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the carpel? What does it consist of?

A

The female part of the flower. Consists of the stigma, style and ovary.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the stamen?? What does it consist of?

A

The male part of the flower. Consists of the anther and filament.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What does the filament do?

A

The filament elevates anther exposing it to wind and pollinators.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What does the anther do?

A

Contains and releases pollen (male gamete)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does the ovule/ovary do in plants?

A

Produces ovule (female gametes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does the style do?

A

Elevates stigma, exposing it to wind and pollinators. Connects the stigma to ovary)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What does the stigma do?

A

Catches pollen from wind and pollinators. (Sticky opening)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What does the sepal do?

A

Thick protective leaves on outside of bud, peel back after blooms.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What does the receptacle do?

A

Connects stem to flower.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What does the petal do?

A

Attract pollinators - vibrant colors.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the difference between ovule and ovary?

A

Ovary contains the ovules.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are 5 features of wind pollinated plants?

A
  • No showy petals
  • No odor
  • Lots of pollen. Dry (not sticky), small, light, aerodynamic
  • Stigma is feathery and sticky. Hangs out of the flower
  • Anther dangles loosely on long filaments move freely in the wind.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

5 features of insect pollinated plants?

A
  • Petals: large and showy colors
  • Delicate and sweet (attractive) odors
  • Pollen is sticky/patterned. Small amounts produced
  • Stigma is small and sticky inside the flower
  • Less anthers inside the flower
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is pollination?

A

The transfer of pollen grains from an anther to a stigma.

31
Q

What is self-pollination?

A

The transfer of pollen grains from the anther of a flower to the stigma of the same flower or a different flower on the same plant.

32
Q

What is cross-pollination?

A

The transfer of pollen grains from the anther of a flower to the stigma of a flower on a different plant of the same species.

33
Q

4 potential effects of self pollination:

A
  • Risk in homozygosity (less genetic diversity)
  • Lack of variation
  • Inbreeding depression - recessive mutations
  • Consistency in the offspring
34
Q

What is an effect of cross pollination on plants?

A

Has the potential to produce healthier plants. This method increases plant species genetic variety.

35
Q

What patterns do bee pollinated plants tend to show?

A

Purple, yellow or white with bullseyes coloration.

36
Q

Do bird pollinated flower have scent?

A

No.

37
Q

What does the prostate gland do

A

Produces fluid called semen that provide sperm cells with nutrients

38
Q

What does the sperm duct do

A

Sperm passes through the sperm duct to be mixed with fluids produced by the glands before being passed into the urethra for ejaculation

39
Q

What does urethra do

A

Tube running down the centre of the penis that can carry out urine or semen, a ring of muscle in the urethra prevents the urine and semen from mixing

40
Q

What does testis do

A

Contained within a bag of skin (scrotum) and produces sperm (male gamete) and testosterone hormone

41
Q

What does scrotum do

A

Sac supporting the testes outside the body to ensure that sperm are kept at a temperature slightly lower than body temperature

42
Q

What does penis do

A

Passes urine out of the body from the bladder and allows semen to pass into the vagina of a woman during sexual intercourse

43
Q

What does oviduct do

A

Connects the ovary to the uterus and is lined with ciliated cells to push the released ovum down it. Fertilisation occurs here

44
Q

What does ovary do

A

Contains ova (female gametes) which will mature and develop when hormones are released

45
Q

What does uterus do

A

Muscular bag with a soft lining where the fertilised egg (zygote) will be implanted to develop into a foetus

46
Q

What does cervix do

A

Ring of muscle at the lower end of the uterus to keep the developing foetus in place during pregnancy

47
Q

Function of flagellum: sperm

A

allows the sperm to swim towards the egg

48
Q

Function of enzymes in head region (acrosome): sperm

A

To digest a route into the egg for fertilisation

49
Q

Function of many mitochondria: sperm

A

To provide energy for movement of the flagellum

50
Q

Function of cytoplasm containing store of energy: egg

A

To provide energy for cell division in the developing zygote after fertilisation

51
Q

Function of jelly-like coating: egg

A

to make an impenetrable barrier after fertilisation to prevent more sperm entering the egg

52
Q

How long does it take for zygote to travel to uterus

A

3 days

53
Q

What is implantation

A

Embryo embeds itself in the thick lining of uterus and continues to grow and develop

54
Q

What happens to fetus in first 12 weeks

A

Major development of organs, nutrients gained from mother by diffusion through uterus lining. Placenta formed

55
Q

What is fetus surrounded by

A

Amniotic sac, containing amniotic fluid (made from mother’s blood plasma) - protects fetus by cushioning it from bumps to the mother’s abdomen

56
Q

What does umbilical cord do

A

Fetus blood supply for exchange of nutrients, removal of waste products

57
Q

What is needed during gestation period (9 months)

A

Glucose, amino acids, fats, water, oxygen

58
Q

How is placenta adapted for diffusion

A

Large surface area, thin wall

59
Q

Why are preganant women advised not to smoke

A

Some pathogenic organisms cannot pass through placenta (acts as barrier) however nicotine can pass through

60
Q

What does fetus blood connect to

A

From placenta by umbilical cord

61
Q

What absorbs waste from fetus

A

Mothers blood, absorbs CO2, urea

62
Q

How does movement of molecules occur over placenta

A

Diffusion, due to difference in concentration gradients

63
Q

What is ovulation

A

Release of an egg, occurs halfway through the cycle (day 14) and egg travels down the oviduct to the uterus

64
Q

When does menstruation occur

A

Failure to fertilise egg - breakdown of the thickened lining of the uterus

65
Q

What is menstrual cycled controlled by

A

Hormones released from ovary and pituitary gland

66
Q

What does FSH do (follicle-stimulating hormone)

A
  • stimulates egg maturation in the follicles of the ovary
  • stimulates follicles in the ovaries to secrete oestrogen
67
Q

What does LH do (luteinizing hormone)

A
  • at its peak stimulates ovulations (release of egg)
  • results in the formation of corpus luteum (temporary collection of cells that form on your ovary)
68
Q

Oestrogen during menstrual cycle

A
  • stimulates the uterus to develop a lining (replace lining lost due to menstruation)
  • post-ovulation, inhibits FSH and LH production in the pituitary gland
69
Q

Progesterone during menstrual cycle

A
  • maintains and thickens lining of the uterus
  • inhibhits FSH and LH production
  • if fertilisation doesn’t occur, levels drop and menstruation occurs
70
Q

Describe all 4 hormones interacting during menstrual cycle

A
  • Pituitary gland produces FSH, stimulating development of a follicle in ovary
  • Egg develops in follicle and follicle produces OESTROGEN
  • OESTROGEN causes growth and repair of the linign of uterus wall and inhibits FSH
  • When oestrogen rises to a high enough level, stimulates the release of LH from pituitary gland, causing ovulation
  • Follicle becomes corpus luteum and starts producing PROGESTERONE
  • PROGESTERONE maintains uterus lining
  • If egg not fertilised, corpus luteum breaks down and PROGESTERONE levels drop
  • This causes mensturation (uterus linign breaks down)
71
Q

What happens to corpus lutem if you are pregnant

A

Continues to produce progesterone, preventing uterus lining from breaking down and aborting the pregnancy

72
Q

What hormone can placenta secrete

A

Progesterone (corpus leutum stops when placent secretes it)

73
Q

How does HIV affect immune system

A
  • mild flu-like symptom after infection
  • virus infects a certain type of lymphocyte of the body’s immune system
  • HIV avoids being recognised and destroyed by changing its protein coat
  • infects certain type of lymphocyte and uses cells machinery to multiply
  • reduces number of lymphocytes, therefore amount of anibodies that can be made
  • Decreases body’s ability to fight off infections eventually leading to AIDS (Acquired Immunodeficiency)
74
Q

How to control spread of STI’s

A
  • limiting number of sexual partners an individual has
  • use condom
  • get tested
  • education programmes

IGCSE Biology (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions